PoS(GRB 2012)106 http://pos.sissa.it/ c ce. mentum (rather than the same binaries which are possible GRB cks are in fact necessary. Further, milar to that of neutron stars. This tions of binary systems within the [email protected] eive natal kicks in order to explain , ining black holes within our Galaxy. mass black-hole formation, one might Physics, Box 43, SE-22100, Lund, jmegen, P.O. Box 9010, 6500 GL e University, 525 Davey Lab, and Steinn Sigurdsson ab ive Commons Attribution-NonCommercial-ShareAlike Licen [email protected] , , Serena Repetto a ∗ [email protected] Speaker. We investigate whether stellar-mass blackthe holes observed have distribution to of rec low-mass X-ray binaries conta Such natal kicks will affect theprogenitors. production of We compact combine BH-NS populationGalactic synthesis potential. with We integra find thatwe in find a that number the of distribution cases, of natal natal kicks ki would seem to be si result is somewhat surprising; in manyhave pictures expected of black stellar- holes tospeed) as receive those kicks given to having neutron the star. same mo ∗ Copyright owned by the author(s) under the terms of the Creat c Melvyn B. Davies Natal kicks of stellar-mass black holes

Lund Observatory, Department of Astronomy and Theoretical Sweden. Department of Astrophysics/IMAPP, Radbound University Ni University Park, PA 16802, USA. E-mail: Nijmegen, The Netherlands. Department of Astronomy & Astrophysics, Pennsylvania Stat Gamma-Ray Bursts 2012 Conference -GRB2012, May 07-11, 2012 Munich, Germany c a b PoS(GRB 2012)106 Melvyn B. Davies have been observed through- binary systems giving the bi- tribution. rious kick distributions. We then ose inferred for neutron stars are of BH-LMXBs using various natal can have two components: one from filled circles). Locations and distances ve received some form of kick when ne due to any natal kick given to the -mass X-ray binaries containing neutron thus should form in the Galactic disc. tic disc. These systems are thought to alactic potential noting their positions are shown in Figure 1. As seen in this of X-ray binaries which can be compared tainties. 2 Galactic distribution, in cylindrical coordinates, of low In Figure 2 we plot the positions in cylindrical coordinates We have used population synthesis to produce a population of Low-mass X-ray binaries containing black holes (BH-LMXBs) kick distributions. Wenecessary find to that produce a natal good match kicks to comparable the observed to BH-LMXB th dis 2. Results Figure 1: naries random kicks with aintegrated natal the kick motion component of the drawn binaries from withinat va a regular model intervals for so the producing G ato synthetic the distribution observed population. stars or black holes:have NS-LMXBs been (open taken from circles) [1] and and BH-LMXBs [2]. Lines ( denote position uncer out the Galaxy. Their positionsfigure, they in are cylindrical found coordinates at aform variety of from distances the from evolution of the Galac massiveThose stars within reaching binaries large and heights fromthe the black disc hole must was formed therefore in ha athe supernova mass-loss explosion. This associated kick with theblack supernova hole explosion on and its o formation. Black hole kicks 1. Introduction PoS(GRB 2012)106 Melvyn B. Davies as a function of distance kicks have been drawn from ks comparable to those given to d Arzoumanian neutron-star kick ynthetic population is a good match ro natal kick. This is also true for kick [5]. fallback of material onto neutron stars. The duced by the ratio of black hole to neutron -star masses. rzoumanian kick distribution [4] (top right), rved systems are shown as large dots. 3 Binary population synthesis for a sample of BH-LMXBs. Natal We conclude that black holes seem likely to receive natal kic In Figure 3 we plot the cumulative distributions of BH-LMXBs Figure 2: Black hole kicks neutron stars. These results are presented in more detail in 3. Conclusion from the Galactic plane.to We see the that observed the distribution distribution fordistributions of [3, both the 4]. s the A very Hansen poor &distributions fit reduced is Phinney by found an for the the ratio case of of black-hole ze to neutron the Hansen & Phinney kick distribution [3] (top left)star or masses the as A would be expected if black holes are formed via whereas the bottom figures correspond to using natalsynthetic kicks population re is shown as small dots whereas the obse PoS(GRB 2012)106 , ApJ , ences for black MNRAS Melvyn B. Davies , (1997) 569 291 nts 2008–4089 and 2011– nce from the Galactic plane, for MNRAS , us grant and Andrea de Luca for hospitality of the Aspen Center for r a reduced Hansen & Phinney natal kick, lation using different natal kicks (dotted line dashed is for a reduced Arzoumanian natal kick, The Black Hole Mass Distribution in the Galaxy 4 The Velocity Distribution of Isolated Radio Pulsars (2004) 355 Investigating stellar-mass black hole kicks 354 ] The pulsar kick velocity distribution MNRAS , The distances to Galactic low-mass X-ray binaries: consequ arXiv:1203.3077 (2010) 1918 Cumulative distributions of BH-LMXBs as a function of dista 725 (2002) 289 submitted [ ApJ 568 hole luminosities and kicks This work was supported by the Swedish Research Council (gra [4] Z. Arzoumanian, D.F. Chernoff, J.M.Cordes, [3] B.M.S. Hansen, E.S.Phinney, [5] M.B. Davies, S. Repetto, S. Sigurdsson, [1] P.G. Jonker, G.Nelemans, [2] F. Ozel, D. Psaltis, R. Narayan, J.E. McClintock, 3991). SR is thankfulhelpful to suggestions. the MBD University and of SSPhysics. gratefully Pavia acknowledge for the the Erasm References short-dashed is for an Arzoumanianwhereas natal long-dashed kick, is short-long- for zero natal kick). Acknowledgments is for a Hansen & Phinney natal kick, dotted-dashed line is fo the observed systems (solid line) and for our synthetic popu Figure 3: Black hole kicks